The nonlinear nature of friction coefficient in lubricated sliding friction

2015 ◽  
Vol 88 ◽  
pp. 8-16 ◽  
Author(s):  
Yuankai Zhou ◽  
Hua Zhu ◽  
Xue Zuo ◽  
Yan Li ◽  
Nanxuan Chen
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Nonlinear Nature ◽  
Lubricated Sliding

The Tribological Behaviour of Beryllium Copper Alloy QBe2 against 30CrMnSiA Steel under Sliding Condition

2011 ◽  
Vol 399-401 ◽  
pp. 2181-2188 ◽  
Author(s):  
Zhi Hai Tan ◽  
Qiang Guo ◽  
Xia Li ◽  
Zheng Ping Zhao
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Copper Alloy ◽  
Sliding Friction ◽  
Tribological Behaviour ◽  
Beryllium Copper ◽  
Wear And Friction ◽  
Volume Wear ◽  
Lubricated Sliding

The tribological behaviour of beryllium copper alloy QBe2 against 30CrMnSiA steel under sliding condition were tested at the M2000A model wear tester. It studied the hardness, surface roughness, load and prior corrosion of QBe2 specimens under the dry or grease lubricated conditions. The volume wear and friction coefficient were relatively better when the hardness of QBe2 was lager under the grease lubricated sliding friction. The volume wear was the smallest when surface roughness was 0.8μm, and its tribological properties were the best under the grease lubricated sliding friction. Meanwhile the values of wear loss, wear rate and average friction coefficient under the grease lubricated friction were one level smaller than that under the dry friction. The volume wear and friction coefficient decreased with the loads declined under the grease lubrication condition. Prior corrosion process made the lubricant effect worse, which obviously reduced the wear-resisting property of QBe2 and enlarged its wear rate and friction coefficient.

scholarly journals Anisotropic Vibration Tactile Model and Human Factor Analysis for a Piezoelectric Tactile Feedback Device

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 448 ◽  
Author(s):  
Jichun Xing ◽  
Huajun Li ◽  
Dechun Liu
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Ciliary Body ◽  
Human Factor ◽  
Sliding Friction ◽  
Excitation Frequency ◽  
Tactile Feedback ◽  
Body Structure ◽  
Full Coverage ◽  
The Coefficient Of Friction

Tactile feedback technology has important development prospects in interactive technology. In order to enrich the tactile sense of haptic devices under simple control, a piezoelectric haptic feedback device is proposed. The piezoelectric tactile feedback device can realize tactile changes in different excitation voltage amplitudes, different excitation frequencies, and different directions through the ciliary body structure. The principle of the anisotropic vibration of the ciliary body structure was analyzed here, and a tactile model was established. The equivalent friction coefficient under full-coverage and local-coverage of the skin of the touch beam was deduced and solved. The effect of system parameters on the friction coefficient was analyzed. The results showed that in the full-coverage, the tactile effect is mainly affected by the proportion of the same directional ciliary bodies and the excitation frequency. The larger the proportion of the same direction ciliary body is, the smaller the coefficient of friction is. The larger the excitation frequency is, the greater the coefficient of friction is. In the local-coverage, the tactile effect is mainly affected by the touch position and voltage amplitude. When changing the touch pressure, it has a certain effect on the change of touch, but it is relatively weak. The experiment on the sliding friction of a cantilever touch beam and the experiment of human factor were conducted. The experimental results of the sliding friction experiment are basically consistent with the theoretical calculations. In the human factor experiment, the effects of haptic regulation are mainly affected by voltage or structure of the ciliary bodies.

scholarly journals Surface Characterization and Tribological Performance of Anodizing Micro-Textured Aluminum-Silicon Alloys

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1862 ◽  
Author(s):  
Luanxia Chen ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Qinghua Song ◽  
Yi Wan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Sliding Friction ◽  
Tribological Performance ◽  
Area Ratio ◽  
Micro Milling ◽  
Dry Sliding ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Aluminum Silicon

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.

A Novel Friction Model Basing on Journal Bearing Theory for Reciprocating Compressor

2013 ◽  
Vol 456 ◽  
pp. 320-323 ◽  
Author(s):  
Le Wang ◽  
Bin Tang ◽  
Yuan Yang Zhao
Keyword(s):  
Friction Coefficient ◽  
Piston Ring ◽  
Sliding Friction ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Dynamic Change ◽  
Friction Model ◽  
Reciprocating Compressor ◽  
Oil Viscosity ◽  
Compressor Performance

The paper presents a comprehensive friction model of reciprocating compressor which is able to evaluate friction losses in moving parts. The model consists of crankshaft, connecting rod and piston all supported by bearings as well as the piston ring/cylinder interface viewed as sliding friction. Hydrodynamic lubrication theory reveals relationship between load and friction coefficient and was demonstrated to be helpful to give insight to the lubrication characteristics of journal bearing. The model gave the composition of friction losses, friction coefficient dynamic change with orbiting angle and effect of oil viscosity on compressor performance. The results showed that the friction losses of piston ring/cylinder interface and the rod big end bearing was most part of the friction losses and it was necessary to choose suitable oil viscosity to reach the optimum compressor performance.

Effect of Graphite Content on Cu–Ni–Graphite Composite for Use as Switch Slide Baseplate Materials Sliding Against U75V Steel

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yiran Wang ◽  
Yimin Gao ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Yunqian Zhang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Mechanism ◽  
High Speed ◽  
Sliding Friction ◽  
Rapid Development ◽  
Wear Volume ◽  
Fatigue Wear ◽  
Friction Coefficients ◽  
Graphite Composite ◽  
Graphite Content

Abstract The rapid development of high-speed railways necessitates the development of new materials for switch slide baseplates. In this study, a Cu–Ni–graphite composite, containing 1 wt% to 6 wt% graphite and prepared by powder metallurgy, was used as a potential material. Pin-on-disk wear tests were conducted to measure the sliding friction of the Cu–Ni–graphite composite against U75 V steel. The results showed that the friction coefficients gradually decreased when the graphite content in the composite ranged from 1 wt% to 4 wt% in the composite. When the graphite content was 4 wt%, the friction coefficient reached the minimum value (0.153). When the graphite content was low (1 wt% to 4 wt%), the primary wear mechanism was microcutting. An increased graphite content facilitated the generation of lubricating films and decreased the wear damage. As the graphite content increased from 4 wt% to 6 wt%, the friction coefficients also increased. The variation in the wear volume rate had the same tendency as the friction coefficient. When the graphite content exceeded 4 wt%, the primary wear mechanism was delamination and fatigue wear. Due to the tendency to form cracks on the subsurface and the plentiful generation of the spalled pits, the graphite fragments could not completely form lubricating films but separated as wear debris. The lubricating films existing on the U75 V steel were in proportion to the graphite content in the composite. The wear weight loss of the U75 V steel exhibited a reduction with increasing graphite content.

scholarly journals Device for Measuring Sliding Friction on Highloft Nonwovens

2006 ◽  
Vol 1 (1) ◽  
pp. 155892500600100
Author(s):  
Stephen Michielsen
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Substantial Portion ◽  
Foam Rubber ◽  
Conventional Steel

When measuring the sliding friction on highly compliant materials such as fabric batting and foam rubber, a substantial portion of the apparent friction is due to the deformation of the substrate. A new friction instrument consisting of a sled within a sled has been developed that eliminates the contribution of this deformation and provides the true sliding friction, as well as the force required to deform the substrate. The friction coefficient as measured using a conventional steel sled sliding on high loft polyester batts increased as the number of polyester batts increased. Using the new, guarded friction sled, the friction coefficient was independent of the number of supporting batts, thus separating the deformation forces from the sliding forces.

scholarly journals Critical shoe contact area ratio for sliding on a tennis hard court

2017 ◽  
Vol 232 (2) ◽  
pp. 112-121 ◽  
Author(s):  
John Eric Goff ◽  
Luke Boswell ◽  
Daniel Ura ◽  
Mark Kozy ◽  
Matt J Carré
Keyword(s):  
Friction Coefficient ◽  
Contact Area ◽  
Sliding Friction ◽  
Static Friction ◽  
Area Ratio ◽  
Critical Ratio ◽  
Static Friction Coefficient ◽  
The Creation ◽  
Contact Area Ratio

Dimples have been used in the design of some modern tennis shoe outsoles to enhance sliding ability on hard courts. Experiments were performed with bespoke rubber samples possessing various numbers of holes, which served to simulate dimples in tennis shoe treads. The aim of the research was to assess the effect of contact area on sliding friction. As the ratio of holes to solid rubber increased, a critical ratio was reached whereby the static friction coefficient decreased by more than 11% for tread-to-court pressures comparable to real tennis play. Although this study analyzed bespoke rubber samples and not actual tennis shoe treads, shoe manufacturers should be interested in the existence of a critical dimple ratio that could aid them in the creation of tennis shoes suited for sliding on hard courts.

scholarly journals Effect of geometrical parameters in micro-grooved crosshatch pattern under lubricated sliding friction

2010 ◽  
Vol 43 (8) ◽  
pp. 1508-1517 ◽  
Author(s):  
Min-soo Suh ◽  
Young-hun Chae ◽  
Seock-sam Kim ◽  
Tatsuya Hinoki ◽  
Akira Kohyama
Keyword(s):  
Sliding Friction ◽  
Geometrical Parameters ◽  
Lubricated Sliding

The Research on the Lubricating Property of Oil-Air Lubrication in the Sliding Friction Element

2013 ◽  
Vol 572 ◽  
pp. 397-400
Author(s):  
Shao Gang Liu ◽  
Li Quan Li ◽  
Jin Li Wang
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Testing Machine ◽  
Wear Testing ◽  
Conical Nozzle ◽  
Rotating Speed ◽  
Friction Element ◽  
Oil Supply ◽  
Air Supply ◽  
Air Lubrication

The influence of the oil supply, nozzle type, air supply, the performance of sliding friction element under the lubrication preloads were investigated by measuring the element’s temperature and friction coefficient based on the M2000-A friction wear testing machine. When the load, rotating speed and air supply is at 1500N, 210rpm and 2.25 m3/h level respectively, as the oil supply is increased, the temperature rises and friction coefficient decreases. The temperature rise decreases monotonically. The friction coefficient rises monotonically with the air supply increases when the air supply is less than 2.4m3/h, but when the air supply is more than 2.4m3/h, the friction coefficient decreases monotonically. Furthermore, when the oil supply is reached 15ml/h, they remain almost unchanged regardless of direct nozzle and conical nozzle. Nevertheless, the direct nozzle is more suitable than the conical nozzle in oil-air lubrication of the sliding friction pairs .

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